It is well recognized that fast and accurate fault determinations in electronic circuits involving component failures or degradation is important. Electronic components and/or circuits or other circuit elements present on circuit boards may fail in the field due to damage or age or they may otherwise degrade sufficiently over time that they may no longer meet the manufacturer's specifications. Failed circuits boards are often tested, instead of being discarded, to determine the source of the failure, which typically would be in one or more components, electrical circuit connections or other elements on the circuit board. Following fault diagnosis, if successful, attempts are typically made to repair the board.
Various testing devices are designed to identify the source of the failed or marginally operative component. These test devices typically include the use of equipment involving either automatic or manual comparison of digital signatures of circuit components while the circuit is operating. One such device is shown and described in U.S. Pat. No. 4,965,516. Such devices include probes which are used to physically contact circuit elements. The test devices using contact probes are typically best suited for circuits operating below 100 MHz. At significantly higher frequencies, i.e. 200 MHz or above, which include most all radio frequency circuits as well as microwave circuits, such devices are typically not effective. In such cases, non contact devices or systems such as shown and described in U.S. Pat. No. 7,496,466, which is owned by the assignee of the present invention, can be successfully used. However, such a system is typically most useful at higher frequencies. In general, it would be desirable for a testing device to be useful with circuit boards which operate with a wide range of frequencies, including both lower (non-RF) and higher (RF and higher) frequency circuit boards.